Giannis isn't and never has been as skilled as Wilt Chamberlain, so I don't accept the comparison.
Wilt wouldn't magically turn into an above-average three-point shooter; if you bring him into this era and he understands that he needs to work on that part of his game, though, I think he could do it. Or more accurately, if you get him when he starts playing ball and develop him into a pro in this era, he could do it. Athletes at the very top of the chain can do anything they're asked to focus on. I'm sure if Wilt really focused on FTs, he could shoot them at a 70% clip or whatever. I'm sure the counter-point there is Shaq, but I don't want to hear anything about Giannis. "Perimeter-oriented" doesn't mean shyt when you have average footwork and no consistent go-to moves out on the perimeter.